Astronomy 101 Final Exam
Astronomers use the term interstellar extinction to refer to:
the scattering and absorbtion of light by interstellar dust
The seven days of the week are named after:
the seven wandering objects in the sky
Many names used by astronomers are misleading or outdated. A good example is the term planetary nebula, which astronomers use to refer to:
the shell let go by a dying low mass star
Why do astronauts (and cans of soft drink) float around in the Shuttle instead of falling?
the shuttle is falling around the earth
Astronomers were at first surprised to find complicated molecules in the interstellar medium. They thought ultra-violet light from stars would break apart such molecules. What protects the molecules we observe from being broken apart?
the significant amount of dust in the clouds protects them from ultra-violet rays
The time it takes for the Sun to return to the same place in our sky after the Earth has rotated once is called:
the solar day
Which statement about the solar month and the sidereal month is correct?
the solar month is more than two days longer than the sidereal month
Someone who observes the sky every clear night in Boston for many years will NEVER get to see:
the south circumpolar zone
Where does the energy come from that allows the Crab Nebula to keep shining almost a 1000 years after the star exploded? (Who ultimately "pays the energy bill"?)
the spinning of the neutron star gives off energy
The terms "a.m." and "p.m." (as in see you at the movies at 8:30 p.m.) derive from what astronomical idea?
the sun passes through the meridian at roughly the middle of the day
Which of the following is an important part of the reason it is hotter in summer in North America than in winter?
the sun's rays hit the earth more directly and spread out less
What would you have to change about the Earth to stop our planet from having significantly different seasons?
the tilt of its axis
A very rich, very shady international banker (with residences all over the globe, including Bayonne, New Jersey) mysteriously disappears. Someone later mails a wide-angle photo of his body to a London newspaper, taken on June 22, showing the Sun exactly overhead at noon. What can the police deduce from this photograph about where on Earth the body is located?
the tropic of cancer (23 degrees N)
On an H-R diagram of a cluster of stars, which characteristic of the diagram do astronomers use as a good indicator of the cluster's age?
the turn off point
Let's say we find a star that is located on the points or circles in the sky listed in the answer choices below. Then, on the same night, we move to a location on Earth that is some significant distance from our first location. There will now be a different star at or on: a. the celestial north pole b. the zenith c. the celestial equator d. the celestial south pole e. all of the above
the zenith
The strip of the sky through which the Sun, the Moon, and the bright planets appear to move in the course of a year is called:
the zodiac
(In the absence of a strong magnetic field), what is the chief factor that determines what type of electromagnetic radiation objects give off:
their temperature
Why is it easier for red giants to lose mass than main sequence stars?
they are so big that the gravity at their surface is less
How did observations with the Compton Gamma-ray Observatory show that gamma-ray bursts were not coming from the Milky Way Galaxy?
they came from all over the sky not just the plane of the galaxy
How do astronomers know that pulsating variable stars are actually expanding and contracting in diameter?
they can measure the shift in the Doppler spectral lines
Why do satellites launched into low-Earth orbits not remain there indefinitely?
they lose speed due to friction with the atmosphere
You and some friends decide (during a wild party held at the time of the Full Moon) that you cannot live without having the secret recipe for the veggie burger they serve in the college cafeteria. So you decide to plan a break-in to steal the recipe from the chef's office. So that you don't get caught, you want to carry out your plan when there is no moonlight in the evening. What is the next phase of the Moon with no evening moonlight (i.e. when the Moon rises roughly at midnight or later)?
third quarter
When the core of a star reaches a temperature of about 100 million degrees (K), something new happens in the core. What is this new event?
three helium nuclei begin fusing cabon
A light curve for a star measures how its brightness changes with
time
The dust in the dust clouds in interstellar space consists of
tiny solid grains
A star whose temperature is increasing but whose luminosity is roughly constant moves in what direction on the H-R diagram?
to the left
From a particular location on Earth, why can we see many more total eclipses of the Moon than total eclipses of the Sun?
total lunar eclipse is visible over a larger area of earth than a total solar eclipse
True or false: astrology has not passed any clear scientific or statistical test and, as a result, most scientists are very doubtful that it can predict anything meaningful about our lives
true
All molecules (like molecules of water or carbon dioxide) are made up of
two or more atoms
In a planetary nebula, the shell of expelled material is glowing intensely. What is the main source of energy for this glow?
ultraviolet radiation
When the outer layers of a star like the Sun expand, and it becomes a giant, which way does it move on the H-R diagram?
upper right
The light which allows you to see this very interesting exam is made up of waves. In these waves, the distance between crests is called the:
wavelength
If you are in a freely falling elevator near the top of a tall building, as the elevator falls, your weight would be:
weightless, zero
he Balmer Series of lines in the hydrogen atom was very important in the history of physics and astronomy. What made it so important?
when electrons change levels to produce Balmer series the emitted light is in the visible part of the spectrum, so the light is easy to see with out eyes
Astronomers identify the "birth" of a real star (as opposed to the activities of a protostar) with what activity in the star?
when nuclear fusion begins
Astronomers studying regions like the Orion Giant Molecular Cloud have observed that a wave of star formation can move through them over many millions of years. What sustains such a wave of star formation in a giant molecular cloud?
when stars form their ultraviolet radiation and later their explosions, compress the gas in the cloud and cause a new formation of stars
A Herbig-Haro (HH) object is
where a jet from a forming star collides with nearby interstellar matter
What stages can only occur in the life of a low-mass star (whose final mass is less than 1.4 times the mass of the Sun)?
white dwarf
When a single star with a mass equal to the Sun dies, it will become a
white dwarf
Astronomers discover a new comet that orbits the Sun, but has its aphelion (the furthest point in its orbit) beyond Neptune. Astronomers studying this comet have the right to expect that it:
will follow Newton's law of motion
How did the world's countries solve the problem that mean solar time varies continuously as a traveler's longitude changes?
wold divided into 24 time zones which each zone keeping the same mean standard time
The point in the sky directly above your head at any given time is called the
zenith
The latitude of the Earth's equator is
0 degrees
The laws of nature (as determined by scientists): are constructed from many observations, hypotheses, and experiments. apply both on Earth and among the stars. can never, ever change once they are written down in textbooks are often written in the language of mathematics.
1 & 2
An astronomy textbook, when printed out, weighs four pounds on the surface of the Earth. After finishing your course, you are so tired of the book, you arrange for NASA to shoot it into space. When it is twice as far from the center of the Earth than when you were reading it, what would it weigh? (Note, assume that the book has been moving away from the Earth, not falling freely around it.)
1 pound
When England and the American colonies finally adopted the Gregorian calendar in 1752, what dramatic change had to be made?
12 days had to be dropped to bring back the seasons into accord
From horizon to opposite horizon, the sky takes up how much angular distance?
180 degrees
A star is 230 light years away. The light we see tonight from that star left it
230 years ago
Light travels 3 x 10^8 meters every second (after rounding). That number in words is
300,000,000 meters
The first ordinary star (other than our own Sun) around which planets were definitely discovered was:
51 pegasi
Credit for the discovery of Neptune is shared by two astronomers. They are:
Adams and Leverrier
The comet-hunting astronomer who made a list of over 100 nebulae and galaxies that could be mistaken for comets was
Charles Messier
The Renaissance astronomer who wrote the pioneering book that suggested the Earth probably orbits the Sun (instead of the other way around) was:
Copernicus
In Copernicus' day, people were worried about the idea that the celestial sphere seemed to turn around us once a day because the Earth rotates. They argued that if the Earth were to rotate so fast, it should fly apart. According to our textbook, what was one response Copernicus had to this worry?
Copernicus argued that the much larger celestial sphere is turning once a day and earth is not meant that the celestial sphere would be torn apart even more
Why was the problem of devising a workable yearly calendar so difficult on Earth?
Earth's rotation period does not divide evenly into its period of revolution
The scientist who first devised experimental tests to demonstrate the validity of the heliocentric model of the solar system was
Galileo
The "prime meridian" (where longitude equals zero) passes through:
Greenwich England
In what fundamental way did the work of Galileo differ from his predecessors who had thought about the sky?
He used instruments instead of relying purely on logic
The period-luminosity relationship for Cepheid variables was discovered by
Henrietta Leavitt
The Earth is closest to the Sun in which month of the year?
January
When NASA and a group of astronomers sent up a spacecraft designed to find planets orbiting other stars, they named it after Kepler. Why was this an appropriate name?
Kepler figured out the rules of planetary motion, which planets in our solar system and planets elsewhere must obey
The planet in our solar system with the shortest period of revolution is:
Mercury
According to the geocentric view, everything in the heavens had to go around the Earth, which was the center of the universe. What objects did Galileo discover with his telescope that clearly didn't go around the Earth?
Moons around the planet Jupiter
In a collapsing star of high mass, when electrons and protons are squeezed together with enormous force, they turn into a neutron and a
Neutrino
The idea that atoms radiate energy only when their electrons move from higher to lower energy levels was first advanced by:
Niels Borh
Small changes in the orbits of planets caused by the gravitational pull of the other planets in the solar system are called:
Perturbations
The great astronomer of ancient times who summarized and improved a system of circles upon circles to explain the complicated motions of the planets (and published the system in a book now called The Almagest) is:
Ptolemy
The astrophysicist who first calculated the highest mass that a dying star can have and still be a white dwarf was
S. Chandrasekhar
Some college students decide to form a secret society that would meet each year after graduation at a time when the day and night were the same length. Which of the following would be a time they could meet?
September 23
The first artificial satellite the human race lofted into orbit was called:
Sputnik
A "New Age" bride and groom, who are enchanted by the Sun, want to get married on the day when it gets to be highest in the sky. If they live in the United States, around what day of the year will the wedding take place?
Summer solstice
At which of the following locations on Earth is the direction we call East not clearly defined?
The North Pole
The ground state in an atom is
The lowest energy state of an atom
Some of the energy produced in the event we call Supernova 1987A was used to blow the star apart. Out of the following places that the energy of this event could go, which absorbed by far the most energy?
The production of a lot of neutrinos
Which of the following is the Earth NOT located in? the solar system the Milky Way Galaxy the Local Group of galaxies The Virgo supercluster
Trick question, its located in all of them
The 17th century astronomer who kept a roughly 20 year continuous record of the positions of the Sun, Moon, and planets was:
Tychro Brahe
What specific event really made it possible for the three laws of planetary motion to be discovered?
Tychro Brahe died and his assistant was able to gain access to his data
A Hertz is
Unit of frequency
The luminosity class of a star tells an astronomer
Whether its a supergiant, giant, or main sequence star
An idealized object that does not reflect or scatter any radiation that hits it, but simply absorbs every bit of radiation that falls on it is called:
a blackbody
When the BeppoSAX satellite, together with telescopes on the ground, helped astronomers pinpoint the location of the first gamma-ray burst to be identified with something that gave off visible light, the burst's location turned out to be in
a distant galaxy
In a supernova like SN1987A, once the crisis of iron fusion has begun, roughly how long does it take the star's core to collapse?
a few tenths of a second
Newton showed that to change the direction in which an object is moving, one needs to apply: a. a force
a force
When astronomers discuss a nebula, what are they talking about? a. the Frisbee-shaped collection of gas that covers the entire Milky Way Galaxy
a giant cloud of dust inbetween or among stars
A type of star cluster that contains mostly very old stars is
a globular cluster
A graduate student is given the assignment to find stars with dusty disks around them. What kind of telescope would it be best for her to use for this purpose?
a large infra-red telescrope
The location of the Earth in the Milky Way Galaxy is
a little less than 30,000 ly from the center
We have two waves of light, A and B. Wave A has a higher frequency than wave B. Then wave B must have:
a longer wavelength
The Local Bubble is
a low density region of interstellar gas extending several hundred ly around the sun
When the mass of a star's core is greater than 1.4 times the mass of the Sun, degenerate electrons can't keep it stable as a white dwarf. Instead, it becomes:
a neutron star
What happens as an electron falls from a higher level to a lower level in an atom?
a photon is given off
Astronomers call a ball of matter that is contracting to become a star
a protostar
An astronomer wants to observe a cloud of cold neutral (not ionized) hydrogen, far away from any stars. What would be an instrument that could help in this task?
a radio telescope tuned to 21 cm
The asteroid belt is
a rocky area between mars and Jupiter
What is a photon?
a self-contained packet of electromagnetic energy
An astronomer wants to observe a cloud of dust in a relatively close part of the Galaxy. Unfortunately, this dust cloud is not located in the direction of a crowded region of stars. What instrument would be the most help in finding this cloud.
a sensitive infrared telescope in orbit around earth
Elements heavier than iron can be created during:
a supernova explosion
An HII region is
a zone around a hot star where hydrogen is ionized
Which of the following statements about Supernova 1987A is FALSE? a. it exploded relatively close to us, in a spiral arm of the Milky Way Galaxy b. it was only visible from the Southern Hemisphere of the Earth c. astronomers believe it was the explosion of a star that was originally a massive type O d. neutrinos from the explosion were actually detected on Earth e. it was observed with instruments in space as well as on the ground
a. it exploded relatively close to us, in a spiral arm of the Milky Way Galaxy
Which of the following statements about our best candidate for long-duration gamma-ray bursts is FALSE? a. it involves the merger of two black holes b. most of the bursts it causes can be shown to be in distant galaxies c. the bursts it produces are more frequently seen and are brighter and easier to pinpoint d. the mechanism involves a special type of supernova explosion e. a rotating, magnetic star corpse most likely produces jets (or beams)
a. it involves the merger of two black holes
Astronomers must often know the distance to a star before they can fully understand its characteristics. Which of the following properties of a star typically requires a knowledge of distance before it can be determined? a. its luminosity b. its radial velocity c. its temperature d. its apparent brightness e. all of the above Submit Your Answer
a. its luminosity
Which of the following has the longest wavelength? a. radio waves b. visible light waves c. ultraviolet waves d. x-rays e. you can't fool me, all these have the same wavelength
a. radio waves
Which of the following statements about open clusters of stars is FALSE? a. they typically contain more mass than any other type of cluster b. their diameters are typically about 30 LY across c. they are found mostly in the disk of our Galaxy d. they are often associated with regions of interstellar matter (gas and dust) e. they can contain stars of a wider range of ages than other types of star groups
a. they typically contain more mass than any other type of cluster
An astronomer observes two ordinary stars. The first one turns out to be twice as hot as the second. This means that the first one radiates:
about 16 times the energy of the second
A dashing Romanian count asks his sweetheart to marry him. She says she will give her reply when the Moon is full. If he asked when the Moon was at first quarter, how long will he have to wait?
about a week
During the period we have daylight savings time, we
add one hour to local standard time
A charming friend of yours who has been reading a little bit about astronomy accompanies you to the campus observatory and asks to see the kind of star that our Sun will ultimately become, long, long after it has turned into a white dwarf. Why is the astronomer on duty going to have a bit of a problem satisfying her request?
after it cools off it becomes to dark to see
The event in the life of a star that begins its expansion into a giant is
almost all the hydrogen hot enough in its core has been turned to helium
Within a constellation, a smaller, recognizable pattern of stars is often called:
an asterism
The smallest piece of an element (like gold or lead) that still has all the properties of that element is called
an atom
Supposing we launched a very fast dart from the Space Shuttle, pointed in some direction away from any planet, so that it could travel beyond the solar system. What would it be most likely to hit first after traveling outward for a while?
an atom of interstellar gas
We now know that the orbit of a stable planet around a star like the Sun is always in the shape of:
an ellipse
If an astronomer wants to find and identify as many stars as possible in a star cluster that has recently formed near the surface of a giant molecular cloud (such as the Trapezium cluster in the Orion Nebula), what instrument would be best for her to use?
an infra-red telescope
You are an astronomer whose supervisor has just forbidden drinking alcoholic beverages near the observatory. In frustration, you undertake a search for alcohol molecules in space. Where would your search be most likely to succeed?
an interstellar cloud of gas and dust
As seen from the continental United States, the Big and Little Dipper
are in the north circumpolar zone throughout the year
Which ancient Greek thinker suggested (long before Copernicus) that the Earth is moving around the Sun?
aristarchus
An eccentric billionaire wants to build a mansion in a location on Earth where the effect of the seasons is the least pronounced -- where summer and winter are not that different. Where should his personal astronomer advise him to build?
at the equator
What happens in the process of fluorescence?
atoms absorb ultra-violet rays and convert them into visible light as their electrons cascade down to lower energy levels
The Astronomical Unit (AU) as defined by astronomers is
average distance between the earth and sun
Which of the following is a reason that astronomers have not found giant planets with the orbit of Neptune around other stars? a. our theories suggest that orbits as far away from a star as Neptune are never stable (and the presence of Neptune in our own solar system is a big mystery) b. Neptune takes 165 years to go around the Sun; getting information about just one cycle of such a planet's orbit around another star would take astronomers 165 years c. at the orbit of Neptune, only very low-mass planets (smaller than Mercury) can form d. the method we are using to find planets currently can only reveal low-mass planets, while we expect high-mass planets at the orbit of Neptune e. you can't fool me; we have already found several planets as far from their stars as Neptune is from the Sun
b. Neptune takes 165 years to go around the Sun; getting information about just one cycle of such a planet's orbit around another star would take astronomers 165 years
Which of the following statements about the International Date Line is correct? a. It runs through Greenwich, England b. When crossing from west to east, you must decrease the date by one day c. It is the only place on Earth where the standard time always equals mean solar time d. The time there is measured with respect to the Moon and not the Sun e. It is a telephone service for meeting single people from other countries
b. When crossing from west to east, you must decrease the date by one day
Which of the following has the highest frequency? a. visible light b. gamma rays c. radio waves d. ultraviolet waves e. you can't fool me, all these have the same frequency
b. gamma rays
Which of the following statements about infrared radiation is TRUE? a. it is the band of the electromagnetic spectrum where each wave or photon has the greatest energy b. it was first discovered in 1800 in an experiment using sunlight and thermometers c. unlike light, infrared can never travel as fast as the speed of light d. while many stars give off infrared, there is nothing on Earth at the right temperature to emit it e. it is the radiation responsible for giving sunburns (or in large doses, skin cancer)
b. it was first discovered in 1800 in an experiment using sunlight and thermometers
Which of the following statements about the way the mass of a white dwarf affects spacetime is correct? a. the white dwarf mass will attract light, and pull it in a curved path; spacetime is not affected b. the white dwarf mass will curve spacetime; light has to follow that curvature c. the white dwarf mass will not affect spacetime at all; only black holes affect spacetime d. the white dwarf mass will have enough gravity to straighten out any curvature in spacetime; so spacetime near the white dwarf will be flat e. since no experiments have ever tested Einstein's theory of general relativity, it is impossible to say what will happen
b. the white dwarf mass will curve spacetime; light has to follow that curvature
Astronomers now have a good idea for explaining how the short-duration gamma-ray bursts might come about. Which of the following is part of their explanation? a. these bursts come from the clouds of comets that surrounds our solar system b. these bursts most likely come from the merger of two neutron stars c. these bursts involve a supernova explosion of a star that has lost its outer layer of hydrogen d. these bursts should easily be observed to have "afterglows" in other wavelengths besides gamma-rays e. these bursts are very common; most of the gamma-ray bursts are short-duration
b. these bursts most likely come from the merger of two neutron stars
Why can a star with a mass like our Sun not fuse (produce) further elements beyond carbon and oxygen?
because it cannot get hot enough to fuse heavier elements
Why is there a 4-minute difference between the solar day and the sidereal day?
because the earth is going around the sun in the course of a year
Why do all stars spend most of their lives on the main sequence?
because the main energy comes from fusion of hydrogen which stars have a lot of
Why can astronomers not tell from what direction a particular cosmic ray started toward the Earth?
because the particles circle around earth
Why do different types of atoms (elements) give off or absorb different spectral lines?
because the spacing of the energy levels is different in different atoms
Because white dwarfs are small, as their name implies, they are hard to see. What is a way astronomers have to find white dwarfs that distinguishes them from main sequence stars?
because they are so hot, scientists use ultraviolet radiation
In the model that astronomers have developed for pulsars, why do they suggest that there must be two beams of energy coming from the pulsar?
because they come from the north and south pole
If most stars are low-mass stars, and low-mass stars typically eject a planetary nebula, why then do astronomers see relatively few planetary nebulae in the sky?
because they expand so rapidly that they are too thin to see
When the authors of our textbook say that astronomers are like police detectives trying to solve crimes, they are explaining that:
both must test their hypothesis against evidence they gather
In a science fiction television show set in the far future, a starship finds itself approaching a stellar association. What types of objects would they be most likely to notice in such an association as they approach?
bright o and b type stars`
How did Henrietta Leavitt "calibrate" her period-luminosity relationship for Cepheid variable stars? In other words, how did she make the general idea into a numerical rule?
by finding Cepheids in star clusters whose distance was known in another way
How did Eratosthenes measure the size of the Earth?
by measuring the hight of the sun of two days on two different cities at different latitudes
Which of the following statements about photons is FALSE? a. photons always travel at the speed of light b. photons each carry a specific amount of energy c. a photon of visible light cannot pass through the atmosphere of the Earth, and thus cannot be seen at the Earth's surface d. high energy photons have a high frequency (when thought of as waves) e. a gamma-ray photon carries more energy than a visible light photon
c. a photon of visible light cannot pass through the atmosphere of the Earth, and thus cannot be seen at the Earth's surface
Which of the following statements about the Crab Nebula is FALSE? a. it is the remnant of a supernova explosion first seen on Earth in 1054 AD b. the nebula still puts out more energy (at all wavelengths) than 100,000 Suns c. inside, there are a number of newly formed massive stars (O and B type stars) d. the neutron star inside shows clear evidence of slowing down just a little bit in its rotation e. we can detect a pulsar inside the nebula using both radio waves and visible lightr
c. inside, there are a number of newly formed massive stars (O and B type stars)
Which of the following statements about the force of gravity is FALSE? a. it is a universal force, which acts everywhere in space b. its strength decreases as the square of the distance c. its strength is inversely proportional to the mass: the more mass, the less gravity d. the force never becomes zero e. it causes the paths of the planets to be ellipses and not straight lines
c. its strength is inversely proportional to the mass: the more mass, the less gravity
Which of the following statements about the main sequence stage in the life of a star is FALSE? a. all stars spend the majority of their lives in the main sequence stage b. during the main sequence stage, energy to power the star is provided by the fusion of hydrogen c. main sequence stars are rare in the Galaxy, so we are lucky to be living around one d. different stars spend a different amounts of time (number of years) in the main sequence stage, depending on the characteristics they were born with e. during the main sequence stage, the mass of any star does not change significantly
c. main sequence stars are rare in the Galaxy, so we are lucky to be living around one
In what location on Earth could an eager math student NOT use her solar-powered calculator at any time at all during the course of a day in June? a. the North Pole b. the equator c. the South Pole d. anywhere on the International Date Line e. none of the above
c. the South Pole
To come up with the precise mathematical form of his law of gravity, Newton first had to invent the mathematical techniques that we now call:
calculus
According to the general theory of relativity, the presence of mass
causes a curvature (warping) of spacetime
On the celestial sphere, halfway between the celestial poles lies the
celestial equator
The minimum speed required to launch an object so that it remains the same distance above the ground and just falls around the Earth is called:
circular satellite velocity
Astronomers now understand that the dark regions or rifts visible in parts of our Galaxy that are otherwise crowded with stars are caused by:
clouds of considerable amount of dust which blocks the light of stars behind them
The light element lithium (which, on Earth, is part of medications that improve the lives of people with mental health illnesses) is more common in cosmic rays than it is in the Sun and the stars. What do astronomers think is the reason for this?
cosmic rays collide with atoms or carbon, oxygen, nitrogen, and break them apart creating more light elements
Which of the following statements about a Type II Supernova is true? a. Type II supernovas happen when a white dwarf is overloaded with mass from a companion star b. Type II supernovas occur in the Milky Way Galaxy just about every year. It's rare to have a year without one happening in the Galaxy. c. A Type II supernova is so faint that we miss most of the ones that happen in our Galaxy d. A Type II supernova occurs at the end of the life of a star with 10 times the mass of our Sun or more e. A Type II supernova is a less powerful explosion than any other type; it can't make any of the elements heavier than iron
d. A Type II supernova occurs at the end of the life of a star with 10 times the mass of our Sun or more
Which of the following types of stars will spend the longest time (the greatest number of years) on the main sequence? a. O b. A c. G d. K e. you can't fool me; every star spends about the same number of years on the main sequence
d. K
Which of these stars will take the SHORTEST time to go from the earliest protostar stage to the main sequence? a. a star 1/10th the mass of our Sun b. a star ½ the mass of our Sun c. a star equal to the mass of our Sun d. a star ten times the mass of our Sun e. all of these stars take the same time to get to the main sequence
d. a star ten times the mass of our Sun
Why do many people consider Isaac Newton one of the greatest scientists who ever lived? a. He formulated the laws that govern all motion in the universe b. He combined the work of Galileo, Brahe, and Kepler into one framework c. He figured out the mathematical form of a law of universal gravity d. all of the above e. none of the above (not a, not b, not c)
d. all of the above
A graduate student in geology who grew up in Florida (near the southernmost tip of the United States) gets to accompany her research professor to the North Pole. What will be different at the North Pole from the way she remembers the sky in Florida? a. the celestial pole is overhead b. the celestial equator is on the horizon c. the way (and whether) the stars rise or set d. all of the above would be different from the way it is in Florida e. all of the above (a - c) would be the same as in Florida
d. all of the above would be different from the way it is in Florida
Which of the following was NOT done by Hipparchus, the great ancient astronomer? a. compiled a pioneering catalog of the positions of hundreds of stars b. created the system of star magnitudes that we still use today c. discovered that the Earth has a motion called precession d. explained retrograde motion e. you can't fool me; Hipparchus did all of the above
d. explained retrograde motion
Which of the following statements about interstellar matter is FALSE? a. 99% of it is in the form of gas b. it is clumpy: much of it is distributed in patchy, irregular clouds c. the total mass in interstellar matter in our Galaxy is about 5% of the mass in stars d. if the matter were spread out evenly, it would be about as dense as the Earth's atmosphere
d. if the matter were spread out evenly, it would be about as dense as the Earth's atmosphere
Which of the following is not a place where astronomers believe interstellar dust grains can form? a. in the cooling winds of material ejected from red giant stars b. in the material flowing out of exploded stars, after it has cooled c. in denser clouds of interstellar matter d. in HII regions e. all of the above are places where dust grains regularly form
d. in HII regions
Which of the following descriptions of interstellar dust is FALSE? a. interstellar dust has a (tiny) rocky core surrounded by an ice mantle b. interstellar dust must be roughly the size of the wavelength of visible light c. interstellar dust must be made of some of the most common elements in the universe d. interstellar dust must be at a temperature equal to the outer layers of a star e. interstellar dust particles can sometimes be found in meteorites and can be identified
d. interstellar dust must be at a temperature equal to the outer layers of a star
To get the distance to a Cepheid variable star, astronomers must take several steps. Which of the following is NOT one of these steps? a. observe the star getting brighter and dimmer to establish that it varies b. measure the period of variations by timing when the star is brightest and dimmest c. estimate the apparent brightness of the star d. measure the star's Doppler shift from its spectrum e. apply the period-luminosity relationship
d. measure the star's Doppler shift from its spectrum
. A fashion designer decides to bring out a new line of clothing which reflects the longest wavelength of visible light. What color will these articles of clothing be to the human eye? a. yellow-green b. blue c. violet d. red e. black
d. red
The amount of interstellar matter present in our Galaxy is always changing. Which of the following processes is NOT a major contributor to that change? a. gas from outside the Galaxy falls into the Milky Way because of gravity b. the powerful explosions that end the lives of massive stars drive material out of the Galaxy c. interstellar matter in dense clouds collapses into stars and is taken "out of circulation" d. some atoms of gas combine in dusty clouds to make more complex molecules e. actually, none of the above is a major contributor to the change
d. some atoms of gas combine in dusty clouds to make more complex molecules
Which of the following is a characteristic of degenerate matter in a white dwarf star? a. helium is actively fusing into carbon b. electrons and protons join together in the nucleus to make neutrons and neutrinos c. the degenerate matter region is expanding as time passes, until it covers a region the size of the orbit of Mars d. the electrons get as close to each other as possible and resist further compression e. the atoms drink, smoke, use bad language, and are attracted to the wrong kinds of particles
d. the electrons get as close to each other as possible and resist further compression
If you could somehow return to the Earth in many millions of years, which of the following will be different? a. the length of the year b. the fact that the Moon shows phases c. the fact that the Earth has seasons Correct Response d. the length of the month e. none of the above
d. the length of the month
Which of the following statements about the nucleus of a typical atom (such as a carbon atom in your little finger) is FALSE: a. the nucleus has an overall positive charge b. the nucleus takes up a very small amount of space compared to the entire atom c. the nucleus contains both protons and neutrons d. the nucleus repels the electrons which move around it e. the nucleus contains most of the mass of the atom
d. the nucleus repels the electrons which move around it
Which of the following is NOT a result of the Earth's precession? a. the Earth wobbles (like a spinning top) with a period of 26,000 years b. where the Earth's axis points in the sky changes over the centuries and millennia c. Polaris will no longer be the North Star in several thousand years d. the stars twinkle when seen from the surface of planet Earth e. the signs of the zodiac most astrologers use are no longer in accord with the constellations in which the Sun is currently found over the course of the year
d. the stars twinkle when seen from the surface of planet Earth
Of the following, which consists of electro-magnetic waves with the shortest wavelength? a. a beam of green light b. TV transmissions bringing us Monday night football c. the sound of the instructor's voice d. the waves of a dental x-ray e. the rays that tan a sunbather on the beach
d. the waves of a dental x-ray
After a nice dinner around the campfire on a camping trip, you and a friend decide to get away from the fire to observe the stars. As you get farther and farther away, you see the brightness of the fire:
decreased as the distance squared
According to Kepler's third law, there is a relationship between the time a planet takes to revolve around the Sun and its
distance from the sun
The way scientists know that a hypothesis in astronomy is a reasonable description of nature is to...
do experiments and observations about the predictions of the hypothesis
Even with the best and largest telescopes, we can't see all the stars in the Milky Way Galaxy, even though these same telescopes can show us other galaxies. Why is that?
dust build up inbetween the stars and blocks the light from stars farther away
Which of the following statements about eclipses of the Sun is true? a. An eclipse of the Sun is visible somewhere on Earth each month. b. When a total eclipse of the Sun is visible, it can be seen over half the Earth each time c. During a total eclipse of the Sun, the Sun moves into the Earth's shadow d. The ancient Greeks and Romans could not see eclipses of the Sun, they are a modern sight that's only become visible to us recently e. For a total eclipse of the Sun to happen, the Moon must get directly in front of the Sun, as seen from Earth
e. For a total eclipse of the Sun to happen, the Moon must get directly in front of the Sun, as seen from Earth
Which of the following stars is a Cepheid variable? a. Sirius b. Betelgeuse c. Rigel d. Mizar e. Polaris
e. Polaris
Which of the following has the greatest density? a. a cubic meter of snow b. a cubic meter of air c. a cubic meter of astronomy textbooks (the printed versions, not the on-line ones) d. a cubic meter of feathers e. a cubic meter of lead
e. a cubic meter of lead
Two stars are giving off electromagnetic radiation. The hotter star will: a. give off more radiation at all wavelengths b. will have a higher average frequency of radiation c. will radiate energy at more than one wavelength d. will give off a continuous spectrum of waves e. all of the above
e. all of the above
Why is it so difficult for astronomers to see new stars in the process of birth? a. birth happens very quickly, so it is hard to "catch" stars "in the act" b. most stars are born inside dusty clouds, which block any light that may be coming from the stars c. the size of a newly forming star is typically quite small and thus hard to make out d. protostars which are not yet doing fusion do not give off a lot of visible light e. all of the above
e. all of the above
Which of the following stages will the Sun definitely go through as it gets older? a. red giant b. source of a planetary nebula c. white dwarf d. black dwarf e. all the above
e. all the above
Which of the following is NOT a way astronomers discover clouds of interstellar matter that have a large amount of dust in them? a. by blocking the light of stars behind them b. by reflecting nearby starlight c. because they make stars behind them look redder than they should be d. by giving off infrared radiation appropriate to their temperature e. by giving off x-rays from hot gas surrounding the dust cloud
e. by giving off x-rays from hot gas surrounding the dust cloud
Which of the following was NOT done by Galileo Galilei? a. turning the telescope to the sky and believing what it showed his eyes b. discovering four large moons around Jupiter c. discovering that Venus goes through phases (like the Moon) d. resolving the Milky Way into many, many stars e. explaining retrograde motion with the heliocentric hypothesis
e. explaining retrograde motion with the heliocentric hypothesis
Astronomers observe a typical star using a telescope and a spectrometer. They will see: a. a continuous spectrum b. an absorption spectrum c. an emission spectrum d. a Doppler shift e. more than one of the above
e. more than one of the above
When white light passes from the air into a different medium such as glass, it: a. is dispersed into different colors b. is reflected backwards c. is refracted (bent) d. is Doppler shifted e. more than one of the above
e. more than one of the above (a & c)
In Newton's Law of Gravity, the force of gravity goes up as the: a. mass goes down b. distance goes up c. mass goes up d. distance goes down e. more than one of the above
e. more than one of the above (c & d)
Some Canadian troops are sent (as part of a U.N. peacekeeping force) to a country located on the Earth's equator. At night, when homesickness makes them gaze sleeplessly at the stars, which of the following will be familiar to them (the same at the equator as in Canada): a. the celestial poles are on the north and south points of the horizon b. the celestial equator is overhead and passes through the zenith c. all stars rise and set (no star remains in the sky all night long) d. all stars are above the horizon exactly half a day e. none of the above are the same on the equator as in Canada
e. none of the above are the same on the equator as in Canada
Which of the following is NOT one of the reasons planets around other stars are so difficult to detect? a. planets don't give off their own light, but only reflect the light of their stars b. planets are small compared to stars, and so don't have much surface area from which to reflect light c. from far away, planets are typically lost in the glare of their parent star d. planets have much less mass than stars e. planets only form very late in the life of a star, just when it is ready to die, and thus last only a very short fraction of the star's life
e. planets only form very late in the life of a star, just when it is ready to die, and thus last only a very short fraction of the star's life
Which of the following is NOT an argument for showing that the Earth must be round: a. during an eclipse of the Moon, the shadow of the Earth is always seen to be round b. when ships travel a large distance away, we see their hulls disappear first and their masts disappear last c. the height of the North Star changes as we travel to different latitudes d. photographs of the Earth from space always show a round body e. the Sun is seen blocking different constellations in the course of a year
e. the Sun is seen blocking different constellations in the course of a year
Which of the following is NOT a result of supernova explosions? a. many of the elements the star fused during its life are blasted out into space b. new heavier elements (including such heavy nuclei lead and uranium) are fused by neutron bombardment during the explosion c. a tremendous flood of high-energy cosmic ray particles is released d. any planets within a few dozen LY of the explosion are bathed with life-threatening radiation e. the neutron star is disrupted and tears apart into many pieces
e. the neutron star is disrupted and tears apart into many pieces
Which of the following statements about electromagnetic radiation is FALSE? a. it always spreads out at the speed of light b. it is given off by all objects that are not at a temperature of absolute zero c. it is typically produced when charged particles oscillate d. different waves of electromagnetic radiation differ in their wavelength or frequency e. the radiation consists of tiny charged particles given off by the nuclei of atoms
e. the radiation consists of tiny charged particles given off by the nuclei of atoms
When stars become giants, which of the following does NOT usually happen? a. their outer envelopes expand significantly b. they lose a significant amount of mass from their outside layers c. their surface temperatures become lower than before d. their overall luminosities increase e. their mass grows significantly as they incorporate planets and interstellar matter near the star
e. their mass grows significantly as they incorporate planets and interstellar matter near the star
Which of the following statements about forces is FALSE? a. forces change the momentum of a body b. forces cause an acceleration to take place c. forces always occur in equal and opposite pairs d. where there is no force, objects continue to move the way they were moving e. there are places on Earth where all forces are absent
e. there are places on Earth where all forces are absent
In the future, several students living on board a space station decide to have a race among different types of electromagnetic radiation. Which of the following travels through space the fastest? a. visible light b. radio waves c. infrared d. x-rays e. you can't fool me, all of these travel through space at the same speed
e. you can't fool me, all of these travel through space at the same speed
The fact that each type of atom has a unique pattern of electron orbits helps explain why
each atom shows different absorption or emission spectra
Recently, the media, always trying to make things sound sensational, have started to call totally eclipsed moon "the blood moon." Why does the Moon look reddish to us when there is a total lunar eclipse?
earth's atmosphere bends the light
How does the Sun influence the tides that we experience on Earth?
effects tides but smaller than moon
In the 19th century, it became clear that magnetism was not a separate force, but was always produced by the action of
electric charges that were in motion
An artist who likes working with sources of light decides to make a modern sculpture out of electrified glass tubes that contain very thin (rarified) neon gas. When the sculpture is finished, and the electricity is turned on, the tubes glow with a rich red color. What we are seeing is:
emission spectrum
To leave the gravitational pull of the Earth, and explore other planets, satellites must have at least:
escape velocity
By the term universe, astronomers mean
everything we can observe
After the core of a massive star becomes a neutron star, the rest of the star's material
explodes outward as a supernova
According to Kepler's 2nd Law, comets (which have eccentric orbits) should spend a lot more of their time
far fro the
If an astronomer wants to find the distance to a star that is not variable and is located too far away for parallax measurements, she can:
find the luminosity class from its spectrum and find its luminosity on the HR diagram
Astronomers have noticed that the visible filaments in the Crab Nebula are moving toward us at great speed. How can they know about motions like this?
from the doppler shift in the line of radiation
As a star becomes a giant, its outer layers are expanding. Where does the energy for expanding these layers come from?
from the fusion of hydrogen into helium in the shell around its core
During what phase of the Moon is the Moon up only during the night hours and all night long?
full moon
What phase of the Moon must it be to have a lunar eclipse?
full moon
Astronomers use the term interstellar matter to refer to:
gas and dust that lies between stars
If you want to find stars that are just being born, where are the best places to search?
giant molecular clouds
The oldest structures in our Galaxy turn out to be
globular clusters
The energy of random atomic and molecular motion is called
heat
When it comes to our place in the solar system today, which model do we accept?
heliocentric
One of the great triumphs of spectroscopy was when astronomers identified a new element in the Sun (one that was only later found on Earth). Today, this element is called:
helium
Cosmic rays are
high speed atomic nuclei, electrons and postirons
Typically, astronomers express the right ascension of a star on the sky in what units?
hours. minutes, seconds
Atoms typically consist of electrons, protons, and neutrons. The most common isotope of one element, however, only has two of these three types of particles. This element is:
hydrogen
The red color we see on a lot of photographs of nebulae comes from which element?
hydrogen
The star now called Kepler-444 is 11 billion years old (much older than the Sun) and has five planets orbiting close to it. What has this system taught astronomers about the history of star formation?
if such an old star has planets close to it when its really warm, those planets must be made of heavier elements. So heavier elements must have formed before the time this star formed
In Australia (in the Southern Hemisphere), when are the days the shortest and the nights the longest?
in late June
Taking astronomy in college ruins you for having any kind of ordinary job, so after graduation you decide to become the leader of a new religious cult. You decide to hold a big religious festival around the time that the days are shortest and the nights are longest in the United States. At what time of year will these celebrations be held?
in late december
You are on a camping trip, far away from city lights. You look up into the dark night sky, and see lots of stars, some brighter, some dimmer. All the stars you see with your unaided eye are
in the milky way galaxy
A single star in the process of forming starts by spinning slowly (while it is quite large and relatively cool.) As the star collapses under the pull of its own gravity, its size decreases. As a result, its rate of spinning:
increase
The idea that objects (in the absence of an outside force) tend to continue doing what they are already doing is called the law of
inertia
You are alone in a large, completely dark auditorium on Earth. What kind of telescope should I use from the other side of the auditorium to detect the electromagnetic radiation emitted by your body?
infra-red
The Julian calendar made the significant advance of:
introducing the leap year
When an atom has lost one or more electrons, it is said to be:
ionized
The most stable (tightly bound) atomic nucleus in the universe is:
iron
Two versions of an element with different numbers of neutrons are called:
isotopes
Why is an absorption spectrum especially useful for astronomers?
it has dark lines that help determine what elements are in the star
The big surprise about the first planet discovered around another regular star was that it
it orbited so close it took only 4 days to go around
The Earth's escape speed (the speed you need to get away forever) is about 25,000 miles per hour. Escape speed depends on the gravity of the object trying to hold the spacecraft from escaping. Based on your understanding of gravity, how will the escape speed from the Moon compare to the escape speed from Earth?
it will be smaller than Earth's
The closest star to the Sun, Proxima Centauri, was recently found to have a planet in its habitable zone. Proxima Centauri is a main sequence star with spectral type M. How would its habitable zone differ from the habitable zone of our Sun?
it would be significantly closer
How long a main sequence star remains on the main sequence in the H-R diagram depends most strongly on
its mass
When a star settles down to a stable existence as a main-sequence star, what characteristics determines where on the main sequence in an H-R diagram the star will fall?
its mass
The scientist who worked out the mathematics of the connections between electricity, magnetism, and light in the 19th century was:
james Clerk Maxwell
Astronomers believe that disks of material will form around protostars that are spinning. What is/are observed phenomena is a good indication of the presence of a disk around a protostar?
jets and herbig-haro objects
A friend of yours who takes her astronomy class very seriously challenges you to a contest to find the thinnest crescent moon you can find just after new moon? What time of day is best for looking for this very thin crescent?
just as the sun is setting or just after
To figure out what you weigh on the surface of the Moon (how much gravity there pulls you downward), you need to know
just the size of the moon's orbit around the earth (semi-major axis)
The number of degrees of arc that your location is north or south of the Earth's equator is called your:
latitude
In the Northern Hemisphere, the altitude (height in degrees above the horizon) of the North Star is always roughly equal to the
latitude of the observer
In locating objects on the celestial sphere, we call the number of degrees east or west that something is from Greenwich, England its:
longitude
How do astronomers learn what elements are present in a given star?
look at the absorption lines in the spectrum
Given the presence of dust throughout the disk of the Milky Way Galaxy, what is the best technique for learning about more distant regions of our galaxy's disk.
look for radiation at long wavelengths like in the infrared region of the spectrum
In figuring out the evolutionary tracks on the H-R diagram, astronomers
make models of the stars on computers and follow how they will change over time
An astronomer discovers a new star and wants to measure its temperature. She would typically do this by:
making a blackbody curve and finding the wavelength of the peak
The planet Neptune was discovered by means of:
mathematical calculations of how it perturbed a nearby planet
What technique did astronomers use to make the first confirmed discovery of a planet around another star like the Sun?
measure the Doppler shift of the lines in the star's spectrum and look for periodic changes in this shift due to the pull of the planet as it orbits the star
An astronomer is observing a single star (and one which does not vary) which she knows is located about 30 light-years away. What was the most likely method she or her colleagues used to obtain that distance?
measure the star's parallax
The largest types of clouds found in interstellar space are
molecular clouds with dust and molecules
Astronomers have found large quantities of cold, neutral hydrogen gas in our galaxy. How is this gas distributed?
mostly in the flat layer disk extending throughout the galaxy
How are globular clusters distributed in our Milky Way Galaxy?
mostly in the halo surrounding the disks of our galaxy
When a planet, in its orbit, is closer to the Sun, it:
moves faster than average
Cosmic rays differ from other forms of interstellar matter by
moving at speeds 90% that of light
Astronomers were surprised to find so many Jupiter-mass planets so close to their stars. According to their best theories and models, such "hot Jupiters"
must have formed farther out and "migrated' inward
Astronomers have long realized that supernovae -- when they explode -- give off an enormous amount of light. But observations of Supernova 1987A (in the Large Magellanic Cloud) revealed that the supernova gives off even more energy in another form? That form is:
neutrinos
What phase of the Moon must it be to have a solar eclipse?
new moon
As a cluster of stars begins to age, which type of star in the cluster will move off the main sequence of the H-R diagram first?
o and b type stars
Biologists tell us that life on Earth took billions of years to evolve into astronomy students and other examples of intelligent life. If we want to search for planets with intelligent life-forms that evolved over the same period of time that we did, what sorts of stars should we not bother searching around?
o and b type stars
As of the time our textbook went to press, 118 different elements had been discovered. All of the ones with atomic number over 92 have been made in physics laboratories. When element 119 (one that has not yet been identified) is found, provided it is like the other artificially made elements, it will:
only be stable for a fraction of a second
Most ultraviolet radiation does not penetrate to the Earth's surface. Instead it is absorbed in:
ozone layer
When a comet like Comet Hale-Bopp comes closest to the Sun in its orbit, we say that it is at:
perihelion
An astronomer is interested in a galaxy called M31, the nearest galaxy that resembles our Milky Way. It is about 2 million lightyears away. Which technique would be able to give us a distance to this galaxy?
period-luminosity relation for Cepheid variables
An astronomy student, for her PhD, really needs to estimate the age of a cluster of stars. What would be part of the process she would follow?
plotting the stars on an HR diagram
The planet in our solar system whose orbit actually brings it inside the orbit of another planet is:
pluto
If an astronomer wanted to find some relatively complex molecules in space, what technique should she use?
point a radio telescope into the regions of the galaxy with a lot of dust
The star that is currently closest to the North Celestial Pole is:
polaris
I want to examine the surface of a planet that is covered by a thick atmosphere (which includes oxygen and contains a very thick layer of water clouds that never clears). What wavelength of electromagnetic radiation would I be smartest to use
radar waves
What kind of telescope did Jocelyn Bell use to discover pulsars in 1968?
radio
Not all wavelengths of electromagnetic radiation can penetrate the Earth's atmosphere. Of the types of waves that come from space, which one are you likely to be able to detect most easily from our planet's surface:
radio waves
When a star or galaxy is moving away from us, we observe the Doppler effect by seeing the lines in its spectrum
red-shift
How could you make an ordinary atom that is minding its own business into an ion?
remove one or more electrons
When a planet temporarily moves westward in the sky over the course of several weeks or months (instead of eastward, as it typically does), we call it:
retrograde motion
If you want to locate someone precisely on the surface of the Earth, you specify her exact latitude and longitude. If you want to locate a star precisely on the sky, you need to specify its exact:
right ascension and declination
Astronomer have concluded that pulsars are
rotating neutron stars
A serial killer from a strange cult only kills his victims when the Moon is full. He leaves a note on the body of his latest victim, explaining that the murder was committed when the Moon was rising. What time of day did the murder take place?
roughly around sunset
A writer of mystery novels wants to portray something gruesome happening just as the full moon is at its highest point in the sky. What time of day will the gruesome event occur?
roughly midnight
The fastest speed in the universe is:
s light
Some of the interstellar gas in our Galaxy has been heated to millions of degrees, a temperature that surprised astronomers when it was first discovered. How do we now think that gas between stars gets that hot?
shock waves from exploding stars heat the gas
If there really were a Santa Claus at the North Pole, what would the cycle of the seasons be like for him and Mrs. Claus?
six months of light followed by six months of dark
A white dwarf, compared to a main sequence star with the same mass, would always be
smaller in diameter
Astronomers observe a young cluster of stars, where stars with three times the mass of the Sun are still on the main sequence of the H-R diagram. Yet the cluster contains two white dwarfs, each with a mass less than 1.4 times the mass of the Sun. If we can show that the white dwarfs are definitely part of the cluster, how can their presence so soon in the life of the cluster be explained?
some stars lose a lot of mass, so they could have started out as massive stars
How fast do electro-magnetic waves travel?
speed of light
When the Sun and Moon are lined up and pull together, the tides they raise are called:
spring tides
A large body in space that consistently makes its own light (instead of merely reflecting another body's light) is called
star
If stars with masses like our Sun's cannot make elements heavier than oxygen, where are heavier elements like silicon produced in the universe?
stars with significantly bigger masses
If you wanted to discover the youngest stars you could find in some grouping of stars in the Galaxy, which type of star group would be the best to search?
stellar associations
When neutron stars were first predicted theoretically, no scientist expected to be able to detect one of them across interstellar distances. What enabled astronomers to find neutron stars in the late 1960's?
strong magnetic neutron star was giving off pulsars
If you could see the new moon, at what time of day (roughly) would it rise?
sunset
Which type of star has the least amount of pressure in its atmosphere?
supergiants
The Stefan-Boltzmann Law relates the energy flux coming from a blackbody (such as a star) to its:
temperature
Wien's Law relates the wavelength at which a star gives off the greatest amount of energy to the star's
temperature
A type of star that has turned out to be extremely useful for measuring distances is
the Cepheid variables
With our current techniques, astronomers can typically only measure the minimum mass of a planet orbiting another star. To know the precise mass of the planet, they must also be able to determine
the angle at which the planet's orbit is tilted in relevance to us
Why does the Moon show phases in the course of a month?
the angle the moons makes with sun changes and we see amounts of reflected light
We observe a glowing cloud of gas in space with a spectroscope. We note that many of the familiar lines of hydrogen that we know on Earth seem to be in a different place. They are shifted toward the blue or violet end of the spectrum compared to their positions in the spectrum of glowing hydrogen gas on Earth. From this we can conclude that:
the cloud is moving towards us
You are an astronomy graduate student and you are observing the big Orion Nebula from an airplane that has a good-sized infrared telescope built into it (there really is such a plane.) On an infrared image of the Nebula, what would particularly stand out?
the clouds of nebula that have a lot of dust in them
The 88 sectors into which astronomers today divide the celestial sphere (the whole sky) are called:
the constellations
What problem has precession caused for many of the schools of astrology?
the constellations are no longer lined up with the astrological signs that they were named after, since astrology was set up, the two have slipped one sign apart
where are the small regions that are the embryos of stars (where individual stars are most likely to be born)?
the cores within clumps of molecular clouds
What observations about disks of dusty material around young stars suggest that planets may be forming in such disks?
the disk show lanes that are empty of dust
A light year is
the distance light travels in one year
Newton's reformulation of Kepler's third law allows us to measure the masses of bodies in orbit around each other, if we can measure:
the distances and periods of revolution
The south celestial pole and the north celestial pole lie in the sky directly above
the earth's axis
If the Earth goes around the Sun, why is the ecliptic not lined up with the celestial equator?
the earth's axis is tilted about 23 degrees
In an ellipse, the ratio of the distance between the foci and the length of the major axis is called:
the eccentricity
The Sun's apparent path around the celestial sphere is called
the ecliptic
The equivalence principle (principle of equivalence) says that
the effects of gravity are equivalent to the effects of acceleration
Why do Cepheid variables have that strange name?
the first star was discovered in the Cepheus constellation
Planck's constant relates:
the frequency of a wave to its energy
What incident in a massive star's life sets off (begins) the very quick chain of events that leads to a supernova explosion?
the fusion of iron
The telescope that allowed astronomers to discover most of the planets found with the transit method was called
the kepler mission
The measurement of cosmic distances was helped tremendously by the discovery, in the early part of the 20th century, that in Cepheid variable stars, the average luminosity was related to:
the length of time they took to vary
How did Supernova 1987A demonstrate that new elements are made in supernova explosions?
the light was kept high by the radioactive elements that decay quickly, they must have been made by the supernova
You are observing a binary star system and obtain a series of spectra of the light from the two stars. In this spectrum, most of the absorption lines shift back and forth as expected from the Doppler Effect. A few lines, however, do not shift at all, but remain at the same wavelength. How can we explain the behavior of the non-shifting lines?
the lines are coming from interstellar matter and not the star itself
The higher the luminosity (intrinsic brightness) a Cepheid variable is,
the longer its period of variation
Among interstellar clouds, the hotter the cloud, the
the lower the density of particles in it
Every celestial object appears to go around the Earth once a day. In addition to this motion, which celestial object has the fastest apparent motion in the sky?
the moon
The natural object (not one that humans built) in space that's closest to Earth is
the moon
The term "baryon cycle," as astronomers use it, refers to:
the movement of interstellar matter in the galaxy into stars and then out when the stars explode
From a city in the U.S., where in the sky would you look to see a star that is not turning with the motion of the sky in the course of a night?
the north celestial pole
Where on Earth do stars always circle the zenith (and never rise and set)?
the north pole
A neutron star is as dense as
the nucleus of an atom
In 1911 Ernest Rutherford did a famous experiment using fast-moving alpha particles as bullets and very thin gold foil as a target. The results of this experiment showed that
the nucleus of an atom was tiny compared to the whole thing
or scientists, an element (like gold) is defined by
the number of protons in its nucleus
The celestial sphere turns once around each day because
the planet of which we live is spinning
To measure how dense a planet is (to know whether it is made of rock or gas and liquid) they must be able to measure the planet's mass from the Doppler shift and
the planet's radius using the transit method
In Ptolemy's system the planets orbit the Earth and not the Sun. How did the system explain the retrograde motion of planets like Jupiter?
the planets moved on a small circle whose center, in turn, circled a point near the Earth
The slow tipping of the Earth's axis in a circle with a period of about 26,000 years is called:
the precession
When a star first begins the long path toward becoming a red giant, a layer of hydrogen around the core begins to undergo fusion. If this layer was too cold to do fusion throughout the main sequence stage, why is it suddenly warm enough?
the pressure from its inward collapse heats it
Christian Doppler discovered what we now call the "Doppler Effect" by measuring:
the properties of sound waves coming from musicians on an open train
The period of the moon's rotation on its axis is
the same as its revolution around the earth
